[Intel-gfx] [PATCH 1/2] drm/i915: Wait for completion of pending flips when starved of fences

[Chris Wilson]

On Tue, Jan 21, 2014 at 10:32:50AM +0100, Daniel Vetter wrote:
> On Mon, Jan 20, 2014 at 9:30 PM, Chris Wilson <chris at chris-wilson.co.uk> wrote:
> > The testcase is only for the trivial reproduction scenario, not the more
> > sporadic situation involving a slightly hungry workqueue, but it is
> > enough to demonstrate the issue and the effectiveness of the simple
> > workaround (for typical userspace).
> 
> Testcase convinced me, this is better than status quo ;-) I guess I'll
> add a short comment though when merging that busy-looping through
> EAGAIN is a but un-neat.

On the other hand, it does reduce the RT problem into a typical priority
inversion issue - all the lock dropping and complex error case handling
is built in and does not need introduction of more fragile code. So
reducing it to a known problem is itself neat. :)
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre